Medium and apparatus for magnetic recording and method for measuring the offset amount

Abstract

A magnetic recording medium includes a discrete area and an offset amount measurement area. The discrete area has a plurality of magnetic tracks where data can be recorded and that has a non-magnetic track where the data cannot be recorded located between the plurality of adjacent magnetic tracks. In the offset amount measurement area, measurement data for measuring an offset amount indicating a relative distance from a center position of the magnetic track to the first head in a direction crossing the magnetic track when the second head is on the center position of the magnetic track can be recorded.

1. A method for measuring the offset amount, which measures the offset amount for a discrete track type of magnetic recording medium including a discrete area that has a plurality of magnetic tracks where data can be recorded and that has a non-magnetic track where the data can not be recorded located between the plurality of adjacent magnetic tracks; and an offset amount measurement area formed only by magnetic material where data can be recorded, the offset amount measurement area being separated from the discrete area, the method for measuring the offset amount comprising:
 recording the measurement data with the recording head while the reproducing head is positioned at a predetermined track in the offset amount measurement area; 
 reproducing the measurement data with the reproducing head while the reproducing head and the recording head are moved in a direction crossing the magnetic track and storing the reproduced measurement data in a storage unit; and 
 performing a plurality of reproducing movements of the reproducing head in a plurality of different positions of the reproducing head and determining the offset amount based on a plurality of measurement data reproduced by the reproducing head and a plurality of measurement data stored in the storage unit, including determining whether a current offset amount for a currently reproduced measurement data is a maximum amount, and when the determining determines that the current offset amount is the maximum, storing the determined offset amount as an optimum offset amount. 
 
   
   
     2. A method for measuring the offset amount, which measures the offset amount for a discrete track type of magnetic recording medium including a discrete area that has a plurality of magnetic tracks where data can be recorded and that has a non-magnetic track where the data can not be recorded located between the plurality of adjacent magnetic tracks; and an offset amount measurement area formed only by magnetic material where data can be recorded, the offset amount measurement area being separated from the discrete area, the method for measuring the offset amount comprising:
 first detecting coming of a sector start signal, and upon that first detecting positioning the reproducing head at a center position of a servo area; 
 second detecting an end of the servo area, and upon that second detecting moving the reproducing head in a radius direction; 
 reproducing the measurement pattern recorded in the offset amount measurement area; 
 repeating the first detecting, second detecting, and reproducing for a predetermined number of sectors; 
 storing an offset amount from the repeating and determining whether a current offset amount is a maximum compared to the stored offset amount; and 
 when the determining determines that that current offset amount is the maximum, storing the determined current offset amount as an optimum offset amount. 
 
   
   
     3. A method for measuring the offset amount, which measures the offset amount for a discrete track type of magnetic recording medium including a discrete area that has a plurality of magnetic tracks where data can be recorded and that has a non-magnetic track where the data can not be recorded located between the plurality of adjacent magnetic tracks; and an offset amount measurement area formed only by magnetic material where data can be recorded, the offset amount measurement area being separated from the discrete area, the method for measuring the offset amount comprising:
 first detecting coming of a sector start signal, and upon that first detecting positioning the reproducing head at a center position of a servo area; 
 second detecting an end of the servo area, and upon that second detecting moving the reproducing head in a radius direction; 
 reproducing the measurement pattern recorded in the offset amount measurement area; 
 repeating the first detecting, second detecting, and reproducing for a predetermined number of sectors; 
 storing an offset amount from the repeating and determining whether a current offset amount is a maximum compared to the stored offset amount; 
 when the determining determines that that current offset amount is the maximum, storing the determined current offset amount is an optimum offset amount; and 
 calculating the offset amount for tracks for which the offset amount has not been measured by utilizing an interpolation with an approximate expression. 
 
   
   
     4. A magnetic recording medium that a composite magnetic head having a first head and a second head can record data on and reproduce data from, comprising:
 a discrete area that has a plurality of magnetic tracks where data can be recorded and that has a non-magnetic track where the data can not be recorded located between the plurality of adjacent magnetic tracks; and 
 an offset amount measurement area formed only by magnetic material where measurement data for measuring an offset amount indicating a relative distance from a center position of the magnetic track to the first head in a direction crossing the magnetic track when the second head is on the center position of the magnetic track can be recorded, the offset amount measurement area being separated from the discrete area, 
 wherein the offset amount measurement area is provided in a track near a center of the magnetic recording medium.